黄芩苷下调NF-κB表达抑制高糖环境下肾小球系膜细胞增殖的作用

目的研究黄芩苷对高糖环境下肾小球系膜细胞（GMC）增殖的抑制作用及对NF-κB表达的影响。方法将体外培养的大鼠GMC分为六组：低糖组,高糖组,黄芩苷低、中、高剂量组、氯沙坦组,培养24、48、72 h。实验结束后根据MTT法检测结果,收集细胞并提取核蛋白,用Western blot方法检测各组NF-κB表达情况。结果高糖组在24、48、72 h时间段的吸光值均较低糖组增高,且随培养时间延长而增高明显（P〈0.05）;黄芩苷低、中、高剂量组,氯沙坦组在24 h时间段吸光值均较高糖组高,48、72 h时间段较高糖组低（P〈0.05）。Western blot结果显示,高糖组NF-κB表达量较低糖组增加。而用黄芩苷干预后,GMC中NF-κB表达量较高糖组减少,且随着浓度增加,表达量逐渐减少。结论高糖环境下体外培养的GMC存在异常增殖现象,黄芩苷能抑制高糖诱导的GMC异常增殖,且呈时间、剂量依赖关系,其机制可能与黄芩苷下调NF-κB表达有关。     

Expression of CYP1B1 but not CYP1A1 by primary cultured human mammary stromal fibroblasts constitutively and in response to dioxin exposure: role of the Ah receptor

The expression of CYP1B1 in human mammary fibroblasts (HMFs) was characterized as a potential modulator of their individual function as well as effects on adjacent mammary epithelia. We have used these characteristics to explore the diversity of fibroblast cells isolated from reduction mammoplasty patients and from different breast locations in breast cancer patients (tumors, peripheral to tumor and skin). These parameters have also been used to examine differences between two donors. The results have shown that while none of these HMFs expressed a detectable CYP1A1 protein basally or in response to TCDD, they all expressed CYP1B1 constitutively at similar levels (0.5-0.9 pmol/mg microsomal proteins) and they were induced by TCDD (up to 5-fold) consistent with mediation by the Ah receptor (AhR). DMBA metabolism by HMFs exhibited high proportions of 5,6-, 10,11- and 3,4-dihydrodiols, a profile that is typical of human CYP1B1 regioselectivity. RT-PCR followed by Southern blot analyses demonstrated that CYP1B1 mRNA expression in HMFs parallels levels of respective microsomal proteins. The AhR is expressed in these HMFs as two cytosolic forms (approximately 106 and 104 kDa) and a substantial proportion of the 104 kDa form was localized to the nucleus even prior to TCDD treatment. In all HMFs isolated directly from collagenase digested breast tissues the AhR is expressed at levels 10-fold lower than in breast epithelial cells. However, HMFs that were isolated after serial passaging of mammary epithelial cultures had shown much higher levels of the AhR expression and more dramatic TCDD-induced down-regulation (>80% in 24 h) associated with more efficient nuclear translocation. These differences suggested the presence of two functionally distinct subtypes of HMFs: interstitial stromal fibroblasts that are readily released by collagenase digestion of breast tissues, and lobular stromal fibroblasts which are more tightly associated with the breast epithelia.